Typewriting machine



Patented Oct. 26, 1937 UNITED STATES TYPEWRITING MACHINE Jesse A. B. Smith, Stamford, Conn., assignor to Underwood Elliott Fisher Company, New York, N. Y., a corporation of Delaware Application April 13, 1936, Serial No. 73,985 10 Claims. (0]. 197-182) This invention relates to efllcient and inexpensive means for illuminating the platen of a typewriting machine.

The line of printing, at the front of the. platen, is overshadowed by the upper portion of the platen, and otherwise darkened, so that it is diflicult to read the printing. Portable machines are often used under adverse conditions; and their compactness increases the undesirable shadowing effect, since the platen is generally mounted low in the frame and close to the ribbon-spool housings.

It is a feature of this invention to convert certain portions of the ribbon-housings into lightreflectors. These portions are adjacent to the platen, and they are given a chromium plating upon their rear vertical faces, to reflect an appreciable light directly upon the work-sheet just in rear of the reflectors, as it feeds around the platen.

It is also an object of the invention to illuminate the printing surface of the platen, by a further organization of reflecting surfaces on the machine-frame at different places in front of the platen. There is efiected a reflection of light .that originates at the rear and above the machine. It reflects onto the entire width of the platen.

Certain of the reflectors are co-operatively arranged to reflect and re-refiect the light, so that rays which normally would be ineifective are redirected against the platen-surface. The reflectors are contained completely within the compass of the machine, and therefore do not interfere with the vision of the operator or the attractive arrangement or appearance or usefulness of the machine.

It is a further object of this invention to make the approach of the end of the work-sheet'visible, so that the operator may be in a position to leave a bottom margin on the sheet and carry additional typing over to a new page. To this end, work-illuminating openings are provided in the centering scale, which in portable machines is usually placed in front of the platen, below the printing point. These openings expose the platensurface immediately above the lower'feed-rolls,

the work on the platen being illuminated by said light-reflecting surfaces, taking advantage of the contrast between the work-sheet and the black platen.

Other features and advantages will hereinafter appear.

In the accompanying drawing,

Figure 1 is a rear perspective view, illustrating the application of the preferred form of this invention to an Underwood portable typewriter.

Figure 2 is a perspective, showing a modification of the invention.

Figure 3 is a fragmentary elevation, showing a second modification.

Figure 4 is a perspective of a portion of the platen-carriage of the machine of Figure 1, showing an opening cut through the scale.

Figure 5 diagrammatically illustrates the illumination of the lower portion of the platen by light rays reflected through the openings in the, scale.

Figure 6 is a fragmentary elevation of the machine of Figure 1, diagrammatically illustrating the co-operative action of the reflecting surfaces.

Figure 1 illustrates the application of the invention to an Underwood typewriter of the portable class having an ornamental mask III which includes a pivotally-mounted ribbon-spool coverplate H, in which ribbon-spool covers l2 are joined at their forward ends by an integral sheetmetal wall I3, which slopes forwardly and downwardly, as shown in Figure 6, and forms one wall of a well l4 within which type-bars l5 are housed. As usual, the type-bars are pivoted in a type-bar segment l8, Figure 2, and are arranged to swing, on the depression of keys ll, into printing position against a platen 18, as indicated in dott lines in Figure 6.

The platen I8 is journaled in end plates l8 0 a platen-carriage IS, the latter slidably carried in runways 20 on anti-friction balls 2|. The platenca'rriage [9 includes a paper-apron 22, lower work-sheet feed-rolls 23, which feed and guide a work-piece 24 around the platen, and upper pressure-rolls 25, which hold the work-piece smoothly against the platen above the printing point. A scale 26, preferably having a concaved vertical section and graduated, as shown in Figure 4, in letter-space intervals, is mounted in the platencarriage l9, and may co-operate in guiding the work-piece after the lower edge thereof has passed the lower feed-rolls 23, as shown in Figure 5. It will be observed that the platen I8 is in close proximity to the ribbon-spool covers 12, a condition typical of the compactly-constructed portable machines; and the pocketing effect of said spoolcovers and the carriage end plates l8 makes ordinary illumination of the ends of the platen difficult.

In the preferred form of the invention, as shown in Figures 1 and 6, rear walls 21 of the ribbonspool covers I2 slope downwardly and terminate in concavely-curving sheet-metal extensions 28.

As shown in Figure 1, outer ends of said extensions do not encroach upon the side walls 29 of the typewriter-mask l0, thus permitting the cover-plate I i to be swung freely about its pivot 23, Figure 6. The walls 21 and extensions 23 may be plated with chromium or nickel, and polished to form eflicient mirror surfaces; or, if preferred, thin, suitably plated and polished metal plates (not shown in Figure 1 or 6) may be secured to the walls and extensions. The contrast between these polished surfaces and the usual black or colored flnish of the machine-frame is pleasing and ornamental.

To illuminate the central portion of the platensurface, that is, the surface between the areas served by the walls 21; there is secured to the inside of the front wall l3 a prismatically corrugated reflector 30, preferably in the form of a thin strip of plated and polished metal. The laterally-extending faces 3| of the reflector are arranged to present surfaces which will reflect the rays of light upwardly against the platen, above the scale 26, as shown in Figure 6. It is obviously preferable to form the reflector with a multiplicity of narrow faces 3|, so that, without impairing its efflciency, the. overall space occupied by said reflector may be kept at a minimum, insuring ample clearance for the type-bar heads 32, which, as shown in Figure 6, rest against a suitable stop 33.

The scale 26, which normally is chromium plated, or given a similar bright flnish to present an operatively eflective contrast with the platen, is made a coordinated part of the illumination system, as presently explained.

As indicated in Figure 6, the printing-point of the platen I8 is very nearly on a level with the top of the ribbon-spool covers l2. This condition is common in portable machines, due to the necessity for compactness. However, the reflecting surfaces are thereby brought below the printing point, and it is obvious that light, when originating at a source above and to the rear of the machine, must be reflected upwardly in order to be efiective, as the printing-point would otherwise remain shadowed by the platen.

It is fundamental that the angle of incidence is equal to the angle of reflection, and the refleeting surfaces must therefore be organized to overcome the obstacles presented by the low and compact machine construction.

The eflectiveness of the reflecting-surfaces in illuminating the platen is ditically illustrated in Figure 6, in which the lines a, b and 0 represent rays of light emanating from a source (not shown) above and to the rear of the platen. It is assumed that the light rays are not focused, that is, that they radiate from the light source in the manner customary in the usual lamp or lighting fixture. Certain of the light rays, designated by the lines a. and 1;, pass into the typebar well 14, and, striking the acutely-angled faces 3| of the reflector 33, are directed rearwardly and upwardly against the platen.

- Other rays, as indicated by the line 0 may approach the machine at a less acute angle, and may strike the walls 21 of the ribbon-spool covers l2, as shown. As the walls 21 are in close proximity to the platen l3, it would obviously be impractical to have the walls slope at such an angle that the light rays could be reflected upwardly against the platen. The use of the scale 26 and the curved extensions 28, however, makes the walls 21 effective as an illumination medium, by re-reflecting the light ray 0, downwardly reflected by the wall 21, upwardly against the platen-surface, and the platen is thereby effectively illuminated.

Referring to Figure 2, it is seen that the reflecting wall 21 of the ribbon-spool cover l2 does not terminate in the extension 28 which characterizes Figures 1 and 6. To supplement said walls 21 and to act in co-operation with the surface of the scale 26, there may be provided a pair of reflecting wings 34, each of which is secured, as by the screws 35, to the upper surface of the type-bar segment it at each side of a type-guide 31. The wings are concavely curved, as shown, and include extensions 38, the upper edges of which lie in close proximity to the lower edge of each ribbon-spool cover wall 21, so as to present a reflecting surface which will be substantially similar in operative effect to the continuous wall 21 and curved extension 23 of Figures 1 and 6.

Adjacent the side walls 43 of the ribbon-spool covers I2, the wings 34 are peaked, as at 4|, to present additional reflecting surfaces. As shown in Figure 2, the previously-described reflector 33 is retained, and said reflector, the reflecting walls 21 of the ribbon-spool covers l2 and the wings 34 act coordinately as shown in Figure 6.

So that this invention may be applied to existing machines, in which the slope of the rear walls 21 of the ribbon-spool covers I2 is so steep as to preclude the use of the walls as eflicient reflectors, a modification is shown in Figure 3. The ribbonspool-housing reflectors may take the form of prismatically corrugated metal reflector plates 45, similar to the reflector 30 shown in Figures 1 and 6. The plates 45 may extend over the full width -of the ribbon-spool housings, and may be secured thereto by integral clips 43 which may pro- .iect through suitable holes in the wall of the ribbon-spool covers and clinch behind said walls.

The reflecting surfaces 41 of the plates 45 are at an angle which will reflect the light rays upwardly, as represented by the lines d, e, and thus illuminate the platen-surface by reflection. The lowest of the surfaces 41 may be formed at a different angle, to cause the reflection of rays which may strike the machine at a less acute angle onto the upper portion of the platen.

To make the approach of the bottom edge of the work-piece 24 visible to the operator, slots or openings 53, Figure 4, may be cut through the scale 26, either near the ends thereof, or at intervals across the full extent of the scale. The openings 50 provide a view of the platen-surface immediately above the forward, lower feed-roll ,23, and, as shown in Figure 5, in which the lines I, 0 represent light-rays, this portion of the platen-surface also will be illuminated by light reflected from the reflecting walls of the ribbonspool covers i2 and passing through the openings 33. v As indicated in Figure 4, the width of the said openings is nearly equal to the width of the scale, and the reflection from the prismatic reflector 45 of Figure 3 must strike the scale 26 at some point within the limits of the openings ill. Adequate illumination of the platen-surface behind the scale-openings is thus assured regardless of which of the types of reflecting surface is employed. 4

It will be apparent from Figure 5 that, after the lower edge of the work-piece 24 has been brought beyond the feed-roll 23 by the usual line-spacing operation, the said edge will be readily visible to the operator by reason of the 11-- lumination. The contrast between the light color of the stationery and the dead black of the platen adds to the effect of the illumination.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. In a typewriting machine having a platen, ribbon-spools mounted adjacent the platen, a mask forming covers for the said ribbon-spools and a downwardly and forwardly sloping web forming a front panel of the machine-frame, means for illuminating the front surface of the platen by reflected light, comprising the combination with reflecting surfaces formed on the said ribbon-spool covers, of reflecting surfaces formed on the said front panel.

2. Means for illuminating the platen of a typewriting machine by reflected light, including, in combination, reflecting surfaces formed on the frame of the typewriting machine near the sides thereof, the said surfaces arranged to cause a downward and rearward reflection of light-rays approaching the machine from a source above and to the rear of the said machine, reflectors adjacent to the first-mentioned reflectors and arranged to re-reflect the said light-rays upwardly against the platen, and reflecting surfaces centrally located in the machine-frame and arranged to reflect light-rays directly onto the platen.

3. In a typewriting machine, the combination with downwardly and rearwardly sloping reflectors located on the machine-frame in front of the platen of the machine and arranged to cause a downward reflection of light-rays striking the said reflectors from a source above and to the rear of the machine, of a second reflecting surface placed adjacent the platen and extending parallel to the axis thereof, arranged to redirect the said reflected rays forwardly away from the platen, and additional reflecting surfaces arranged to co-operate with the said second reflecting surface to cause the reflection of the rays from the second surface rearwardly and upwardly against the platen.

4. Means for illuminating the platen of a typewriting machine by reflected light, including, in combination, reflecting surfaces formed on the frame'of the typewriting machine near the 'sides thereof, the said surfaces arranged to cause a downward and rearward reflection of light-rays approaching the machine from a source above and to the rear of the said machine, and additional ctr-operating surfaces arranged to re-direct the said rays upwardly against the platen, one of said additional reflecting surfaces comprising a paper-centering scale mounted adjacent to the platen.

5. Means for illuminating the platen of a typewriting machine by reflected light, including, in combination, reflecting surfaces formed on the frame of the typewriting machine near the sides thereof, the said surfaces arranged to cause a downward and rearward reflection of light-rays approaching the machine from a source above and to the rear of the said machine, and additional co-operating surfaces arranged to re-direct the 'said rays upwardly against the platen,

one of said additional reflecting surfaces comprising a paper-centering scale mounted adjacent to the platen, the said scale formed to permit a portion of the light reflected thereagainst to penetrate to the platen-surface, permitting an illumination of a portion of the said platen behind the scale.

6. In a typewriting machine having a frame, a platen mounted in a platen-carriage in said frame, and reflecting surfaces on said frame arranged to reflect light in the direction of said platen, a paper-and-line centering scale arranged to be mounted in front of the said pla the said scale having a reflecting surface ranged to act in co-operation with the other reflecting surfaces in illuminating the platen, and having windows formed in the scale through which the platen-surface behind the said windows may be illuminated.

7. In a typewriting machine, means for illuminating the platen of the said machine by reflected light, comprising, in combination, a reflector centrally located with respect to the machine and arranged to reflect light-rays upwardly against the platen, and an organization of additional reflecting surfaces by which downward reflection of light is re-directed upwardly against the platen.

8. In a typewriting machine, means for illuminating the platen of the said machine by reflected light, including a series of reflectors mounted in front of the platen, the said reflectors being formed with prismatic surfaces by means of which light originating above and to the rear of the said platen may be reflected rearwardly and upwardly against the platen.

9. A platen-illuminating member for a typewriting machine, comprising housings for the ribbon-spools of said machine, said housings connected. at their forward walls and held in spaced relationship by a web disposed in front of the type-basket of said machine, and reflecting surfaces provided on said web and on said ribbon-- spool housings arranged to reflect light-rays against the surface of said platen.

10. In a typewriting machine, the combination with a reflector placed adjacent the platen and in parallel relationship thereto, the reflecting light-rays toward the platen, the last-mentioned reflectors having extensions arranged to intercept the rays reflected away from the platen by the first-mentioned reflector and re-direct them against the platen.

JESSE A. B. SMITH. 

